The Jamaican, then 21, was already the world record holder but lowered the mark to 9.69 seconds, easing clear of his rivals and celebrating before he crossed the line.
An anticipated battle with countryman Asafa Powell did not materialise, with Powell missing out on a medal altogether as Richard Thompson of Trinidad and Tobago finished second and American Walter Dix took bronze.
Bolt said afterwards: “My one aim was just to be a champion. That is what I came here to do. I told you I was going to be number one and I did just that.
“I got a great start. I was getting good starts all the way up to the final. I was getting better and better. It was crazy – phenomenal.”
Bolt went on to win gold in his favoured 200m and the 4x100m relay – a feat he repeated in unprecedented fashion at the 2012 and 2016 Games, although he was subsequently stripped of the Beijing relay medal after team-mate Nesta Carter tested positive for a banned substance.
He continues to hold the world records in the 200m and 100m, which he lowered to 9.58secs in 2009.
Bolt retired after the World Athletics Championships in 2017 but made a short-lived attempt to become a professional footballer the following year.